Teleradiology is the process of sending radiologic images from one point to another through digital, computer-assisted transmission, typically over standard telephone lines (POTS), or over a wide-area network (WAN) using dial-up ISDN lines or other switched digital services. Using teleradiology, images can be sent from one part of a hospital to another part of the same hospital, from one hospital to another, from remote sites to diagnostic centers, etc. In other words, images obtained at one location can be sent to almost any place in the world.
As cost-effectiveness in medical diagnostic imaging becomes a major issue, teleradiology (remote radiology or the transmission of radiologic images) is becoming an acceptable way to make diagnoses and to consult with referring physicians. Teleradiology has been called the "great equalizer for radiology" and it has allowed normal practice limitations like distance, licensure and reimbursement to be largely eliminated. Computer-assisted transfer of digitized images allows geographically dispersed consultants to lend their expertise to remote regions, thereby benefiting patients who now may have limited access to radiological services. Teleradiology systems especially are important to rural medical facilities.
Teleradiology requires trade-offs of image quality (that is, image quality sufficient to perform accurate diagnosis) with system cost and image transmission time.
Although some teleradiology systems have been implemented using standard, off-the-shelf equipment, effective teleradiology typically requires expensive, specialized equipment as well as persons trained in its operation, maintenance and use. As a consequence, in remote locations where teleradiology would be of most use, it is unlikely to be readily available. As noted in a recent article on the subject, "[a]lthough technological advances continue to drive decreases in system prices, teleradiology and telemedicine continue to face significant challenges." 17/2 Health Management Technology Feb. 22, 1996.
Low-cost teleradiology systems developed using standard, off-the-shelf components suffer from various problems. For example, in one system "the image digitization time . . . was quite long." Low cost digital teleradiology, Reponen J. et al, 19/3 EUR. J. RADIOL. 226-231, 1995.
Radiographic images (X-rays) typically contain vast amounts of information. It is therefore desirable to be able to compress the images, especially in a teleradiology system where the images are to be electronically transferred to remote locations in a reasonable amount of time.
In many radiographic images, areas which do not depict tissue or other regions of interest (ROI) may be eliminated to reduce the amount of data managed by systems and transferred between systems. Segmentation or partitioning of an image may also enable more efficient data compression of the image. Segmentation schemes using complete images have been used.
In the specific area of telemammography, results have been mixed. One study concluded that further improvements in hardware and imaging parameters may improve detection of soft tissue abnormalities and that further evaluation is necessary to determine whether teleradiology might be applicable to breast cancer screening. Detection of breast abnormalities on teleradiology transmitted mammograms, Fajardo L. L. et al., 25/10 INVEST. RADIOL. 1111-1115, 1990.
It is therefore desirable and useful to provide teleradiology for mammograms which achieves a good balance of the quality/cost/time trade-off. That is, it is desirable to provide teleradiology for mammograms using standard imaging, computer and communication equipment while still achieving acceptable results.
It is also desirable to segment images in real-time (or almost real-time) as they are obtained from an image acquisition system (for example, a film digitizer).